Chiral amines are ubiquitous functionalities found in the architecture of the natural world and have been embedded into materials, catalysts, pharmaceuticals, agrochemicals, and bioactive natural products. However, limited approaches are accessible for the construction of an enantioenriched tertiary or quaternary-containing amine. This thesis describes the development of new methodologies for the synthesis of 7-membered nitrogen-containing heterocycle and 1,2-diamine compounds.
Chapter one describes the application of dynamic kinetic asymmetric amination (DYKAT) of branched allylic acetimidates in the synthesis of 2-alkyldihydrobenzoazepin-5-ones. These 7-membered-ring aza-ketones are generated in good yield with high enantiomeric excess through sequential rhodium-catalyzed allylic amination with 2-amino aryl aldehydes followed by intramolecular olefin hydroacylation of the resulting alkenals. This two-step procedure is efficient, straightforward and convenient for the enantioselective preparation of these ring systems.
In Chapter two, we further extended the methodology towards the allylic amination of racemic secondary and tertiary allylic trichloroacetimidates possessing β-nitrogen substituents, and proximal nitrogen-containing heterocycles, using the DYKAT transformation to provide branched allylic 1,2-diamines with high enantioselectivity. The catalytic system is versatile in the synthesis of 1,2-diamines possessing two contiguous stereocenters, with excellent diastereoselectivity. Additionally, the nitrogen-containing heterocycles suppress competing vinyl azirdine formation, allowing for the high enantioselective syntheses of 1,2-diamines possessing tertiary and quaternary centers. Chapter three gives a very brief outlook on our efforts in rhodium-catalyzed amination strategy in providing access to a variety of enantiopure α-fluoromethylated allylic amines.